Need help identifying fuel pump relay on 5/93 530iA

Hi, i am checking the car no start issue on my 5/93 530iA V8. Trying to do the fuel pump jumper #30 #87 relay to see if FP is the issue or has power. Can someone with same car tell me which relay in the pic is for fuel pump? Bentley manual shows the fuel pump relay schematic looks like what's on the orange one but reading the forum someone says the blue one. I am confused now.

I have checked so far:
Battery- ok
Fuse 23- ok
Stomp test - no code showing, engine light not blinking
CPS - not sure how it looks like or where at yet

Thanks in advance

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Can' give an answer to which one for the relay. However if you temporally disconnect the wire that triggers the starter motor you can than get a friend to hold the key in the start position withouit the engine turning over. While the key is being held in 'start' you can get to listen at the tank to know if the pump is running. If it is you can pull the relays one at a time until it does not come on. If it does not run the you know the problen and can go on from there. Maybe check if the motor leads are getting power and earth. If the pump runs but no fuel at engine: try a new fuel filter.

Orange.

In any case, if you look at the circuit diagrams on the side of every electrical relay, you'll be able to tell which ones you need to jump on the circuit board in order to close the circuit. There will be an open circuit on the diagram between two leads and those are the ones you'll need to close. So number 30 and 87 on the orange one is what you're looking for.

In any case, replace it with a new one. It would go at some point. I bet your no-start issue is either the fuel pump, fuel pump relay, or the CPS. These are very well known no start issues for the E34. I hope you'll get them all done right away.

Thanks guys for your replies! Will try to jump the Orange and see if fuel pump gets power. I read it somewhere that I don't need to turn the key to position 1 or 2, the power will go straight to the fuel pump directly. I am still not sure how long does power stay with fuel pump when jumping #30 ad #87 socket, like does it stay on for 2 to 3 seconds and shutoff power? will see then. The power connector at the pump seem hard to take it out, do I slide it to the side first, then pull it out? or is there a trick to it?

Pump will have power all the time the jump wire is in place, independent of ign key position - presuming fuses are ok.

When i closed #30 and #87 socket where the orange relay plugged, i see no power going to sockets/terminals at the fuel pump. Bentley 160-6 fig. 9 says to check using terminals 4(-) and 5(+). I followed the terminals illustration on fig. 10. No matter if i jump #30 and #87 or not i dont see any power. I set voltmeter to 12v DC, is this right or should be ohms? Terminal 1 and 3 has 5.6 mV no matter if i jump 30 87 or not. When i turn key to 2nd position not starting though, terminal 1 and 3 has power. Terminal 4 and 5 also still has no power. Any idea if terminal 4 and 5 is correct?
I also did not hear FP making any noise when cranking, also tried hitting on the gas tank or top of fp a little, no help..

I still questioning whether the orange relay is really the fuel relay. In the fuse box otherside driver side, there are like 2 or 3 orange color relay too with exact same schematic on it.. i wonder if i am jumping wrong FP relay....





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And please check your fuse box. Current will not run if your fuel pump fuse is busted even if the relay is jumped.

Any relay that is jumped should record current, unless there is more than 1 relay in that circuit, in which case just switching the key to position 2 ("key2") would be enough to rule that out.

First resort - Try putting 12v directly on the terminals of the pump. Then you will know if will run. Then work your way back to fuses and relays under the hood (bonnet). Keep your meter on volts. You should fond 12v in the base plug of just about all the relays if their fuses are good. (OK a simplification)

Roberto, yes I already checked the fuse pump (Fuse 23) in the fuse box (driver side) and the fuse itself is good, not busted. I took the fuse out and try it on the battery directly, and 12V voltage is going thru OK. I also tried plug in the spear fuse that's in the box, also didn't help the pump to get any power.


BWMFather, yes, plugging 12V directly to the fuel pump sounds like a good idea, but I'm a bit hesitate to put 12V directly on the pump while the pump is still sitting directly inside the gas tank. If terminal 4(-) and 5 (+) are not correctly match with the Bentley manual, I'm afraid this might cause any spark from the battery to the fuel tank and perhaps cause fire/bad incident. I'm thinking maybe if I take the fuel pump out from the fuel tank first and then hook to terminal 4 and 5, might be a safer approach. I also read that it's not recommended to run the pump without fuel as the fuel is treating as lubricant, maybe running the pump outside in the air for 1 to 2 second is not too bad I guess?


As I am still a newbie, your other suggestion of "disconnecting the starter motor" wire, I'm putting that in the back of my head for now, as I'm still not sure where that cable is at the moment, still learning the components/wires in the hood.

on a side note, as I've been cranking and trying to start the car a few times in the past, the battery voltage has drained down to 12.05V, and after connecting to the car, it drops even more to 11.88V.
Regardless that it's below 12.xxV, I think I still should get some voltage close to 11.xx if jumping #30 and #87 on the fuse pump relay socket (Orange relay) if everything is correctly connected, correct me if I'm wrong.

BTW, this car was first sold in Canada, and shipped to USA, not sure if this helps solve any mystery of the fuel pump relay etc...


Thanks much!

Originally Posted by JackNB

Roberto, yes I already checked the fuse pump (Fuse 23) in the fuse box (driver side) and the fuse itself is good, not busted. I took the fuse out and try it on the battery directly, and 12V voltage is going thru OK. I also tried plug in the spear fuse that's in the box, also didn't help the pump to get any power.


BWMFather, yes, plugging 12V directly to the fuel pump sounds like a good idea, but I'm a bit hesitate to put 12V directly on the pump while the pump is still sitting directly inside the gas tank. If terminal 4(-) and 5 (+) are not correctly match with the Bentley manual, I'm afraid this might cause any spark from the battery to the fuel tank and perhaps cause fire/bad incident. I'm thinking maybe if I take the fuel pump out from the fuel tank first and then hook to terminal 4 and 5, might be a safer approach. I also read that it's not recommended to run the pump without fuel as the fuel is treating as lubricant, maybe running the pump outside in the air for 1 to 2 second is not too bad I guess?


As I am still a newbie, your other suggestion of "disconnecting the starter motor" wire, I'm putting that in the back of my head for now, as I'm still not sure where that cable is at the moment, still learning the components/wires in the hood.

on a side note, as I've been cranking and trying to start the car a few times in the past, the battery voltage has drained down to 12.05V, and after connecting to the car, it drops even more to 11.88V.
Regardless that it's below 12.xxV, I think I still should get some voltage close to 11.xx if jumping #30 and #87 on the fuse pump relay socket (Orange relay) if everything is correctly connected, correct me if I'm wrong.

BTW, this car was first sold in Canada, and shipped to USA, not sure if this helps solve any mystery of the fuel pump relay etc...


Thanks much!

My friend, it is quite probable that the reason why your jump didn't work is because the fuel pump is busted. Plain and simple.

There's another way to zero in on this. Pull out the fuel pump's connector in the trunk (you'll have to remove the carpet and the cover). Use your multimeter's leads to confirm that current is going to the appropriate connections (check bentley). If it is, and your car is not starting, then your fuel pump is probably screwed.

Not sure why there's no fuel pump code though.

In any case, you should be changing the fuel pump, the fuel pump's O ring, the fuel pump relay, and the crankshaft position sensor, to a new one, to avoid commonly known no-start issues peculiar to E34s of this age.

Originally Posted by JackNB

When i closed #30 and #87 socket where the orange relay plugged, i see no power going to sockets/terminals at the fuel pump. Bentley 160-6 fig. 9 says to check using terminals 4(-) and 5(+). I followed the terminals illustration on fig. 10. No matter if i jump #30 and #87 or not i dont see any power. I set voltmeter to 12v DC, is this right or should be ohms? Terminal 1 and 3 has 5.6 mV no matter if i jump 30 87 or not. When i turn key to 2nd position not starting though, terminal 1 and 3 has power. Terminal 4 and 5 also still has no power. Any idea if terminal 4 and 5 is correct?
I also did not hear FP making any noise when cranking, also tried hitting on the gas tank or top of fp a little, no help..

I still questioning whether the orange relay is really the fuel relay. In the fuse box otherside driver side, there are like 2 or 3 orange color relay too with exact same schematic on it.. i wonder if i am jumping wrong FP relay....


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Jump terminals 30 and 87, and then try to start the car. If it works your fuel pump is working fine and your relay was busted. If it doesn't work, you'll need to check if your crankshaft position sensor is working fine. You'll have to find that.

If your fuel pump is ok, with the bonnet off, you should hear some slight noises from the engine bay when you key2 the ignition (put your key into position 2, aka key2). This is the sound of your fuel system pressurising itself. When you're at key0, and you jump those two relays, you should hear the same sounds as well as your fuel pump would have received current and would be similarly pressurising the engine. At least that's how it works on my m50 engine.

If you hear that pressuring noise in your engine while its jumped and you still can't start the car, then your crankshaft position sensor is busted. If you can hear the slight noise with the relay fixed in and when you key2 the car, then both your fuel pump and its relay are working fine.

I am assuming that you can crank your engine. Forgot to double check that with you, should have done that much earlier apologies. If you can't even crank the engine, you've got a dead starter, dead ecu or a dead or weak battery. The first two are unlikely but the last one is likelier, and only requires a jump start to fix.

If the device is dead, jumped connectors on the relay socket will not flow current. The circuit remains open.

Xlnt idea to check for 12v across the pump connector. Probably easier than putting 12v on the motor. If you do put 12v on the motor I would suggest that either leaving it in the tank is safe (fumes sealed inside the tank) or bench test well away from the vehicle. Running for a few seconds won't hurt. I suggest no more than 5. Beware it is a high torque device and will jump when first connected on the bench. Change the fuel filter(s)!!!

Originally Posted by robertobaggio20

Jump terminals 30 and 87, and then try to start the car. If it works your fuel pump is working fine and your relay was busted. If it doesn't work, you'll need to check if your crankshaft position sensor is working fine. You'll have to find that.

I don't remember if I try cranking/starting the car when jumped #30 and #87, let me try that next time to see if car will start. I did try swapping the orange relay getting from the fuse box (driver side) with the same orange relay in the E-box (passenger side). Assuming FP relay is in the E-box. Still, it cranked, but won't start. However, battery was already low at 11.88V, so orange relay swapping test here isn't worth it.

If your fuel pump is ok, with the bonnet off, you should hear some slight noises from the engine bay when you key2 the ignition (put your key into position 2, aka key2). This is the sound of your fuel system pressurising itself.

Bonnet? do you mean the front hood of the car? Yes, I hear some pressuring noise from the front engine when key is at position 2 (where all those red lights on dash comes on before cranking engine). I hear this noise from front of engine even without jumping FP relay (#30 and #87), FP relay is in the socket. However, I do not hear any noise from fuel pump itself. There's another fuse box(?) under the back seat too, also has some relay there too.

When you're at key0, and you jump those two relays, you should hear the same sounds as well as your fuel pump would have received current and would be similarly pressurising the engine. At least that's how it works on my m50 engine.

When jumping #30 and #87 FP relay socket, I did not hear any noise from front of engine when key is at 0 position (car off),everything from the car quiet when jumping. Now I can't really remember if I had the car key in the ignition when jumping FP relay #30 and #87 or not, key might be in my pocket, does key has to be in ignition to get current/voltage to the fuel pump when jumping #30 and #87? I assume it doesn't matter, but I'm just guessing here. I should probably retry with key in 0 position (like just push key into ignition and not turn anywhere).

If you hear that pressuring noise in your engine while its jumped and you still can't start the car, then your crankshaft position sensor is busted. If you can hear the slight noise with the relay fixed in and when you key2 the car, then both your fuel pump and its relay are working fine.

Nope, didn't hear anything when jumping #30 and #87 socket. I need to retry starting the car when jumped #30 and #87 and see.

I am assuming that you can crank your engine. Forgot to double check that with you, should have done that much earlier apologies. If you can't even crank the engine, you've got a dead starter, dead ecu or a dead or weak battery. The first two are unlikely but the last one is likelier, and only requires a jump start to fix.

Yes, I can crank the engine fine, it just won't fire up the car. I tried recharge the car battery up to 12.60V before and trying to crank again, but still no help. This is a new battery just bought, so I don't think battery is the problem at this point.

Originally Posted by robertobaggio20

If the device is dead, jumped connectors on the relay socket will not flow current. The circuit remains open.

Which device are you talking about? fuel pump? When I check the current/voltage at fuel pump, I checked at the fuel pump connector/socket that was disconnected from the fuel pump. Are you saying the fuel pump socket/connector has to attach to fuel pump for circuit to flow so I can check the power with voltmeter?

Originally Posted by BMWFatherFigure

Xlnt idea to check for 12v across the pump connector. Probably easier than putting 12v on the motor. If you do put 12v on the motor I would suggest that either leaving it in the tank is safe (fumes sealed inside the tank) or bench test well away from the vehicle. Running for a few seconds won't hurt. I suggest no more than 5. Beware it is a high torque device and will jump when first connected on the bench. Change the fuel filter(s)!!!

I would probably feel more comfortable doing the bench test of the motor than directly put 12V on the pump motor while it's sitting inside the sealed gas tank. The reason is I'm not very sure if the pump connector schematic is correct as I'm still guessing. Anyone out there try putting 12V from battery directly on fuel pump before? Do we need any resistance in between to reduce the 12V to something lower? Is the spec of the fuel pump can take 12V directly without damaging the pump circuit? I assume someone had tried it before and worked fine??

Volts will show between a power wire and earth when the wire is live. Volts will show across the connector PROVIDING the socket is live and the earth is good. Current is measured in AMPS. Do not set your meter to AMPS or OHMS. Leave it on VOLTS. It sounds like you have not yet located the FP relay.

Oh I'm such a dud. Its simple to test if the fuel pump is working or not. Just check for continuity.

Bentley tells you which sockets in the fuel pump's connector should possess current. Just switch your multimeter to check continuity in the exact CORRESPONDING prongs on the fuel pump. Switch your multimeter to ohms, low ohms, If it shows, 0, 1 or -1, i.e. no continuity, then the device is dead. No continuity means current cannot continuously flow from one point to the other. There is a break somewhere. That is not normal and usually means the circuits are dead. And if there's no continuity at the fuel pump, that means that even when you connect the fuel connector back to the FP's prongs, current will not be able to flow from the battery through the pump and back to the battery again.

Anyway, from the sound of it, it looks like your fuel pump is working (pressuring sound from the engine) and your fuel relay is not the problem ( no change when you swop with the exact relay from elsewhere in the car). Your fp's fuse is also ok.

Then I think your crankshaft position sensor is screwed. Pull the codes from your car, you should have a CPS code (there are lists of codes on the internet).

If you don't have a code reader or the stomp test does not work, find and unplug the CPS, then test it for continuity. Bentley has details. If it doesn't, then purchase a new one and swop it in. In any case, you should purchase a new one and swop it in, the CPS will fail at some point or the other and you've already wasted so much time with this thus far (which is why the sticky at the top of the list emphasises killing known no-start situations ahead of time).

Only buy OEM. While you're at it, purchase an OEM FP, FP's o ring, and an FP relay. Swop them all in when you have the time.

I put genuine Bosch CPS in my E23. $ cheaper and the OEM part. Bypass the stealers go to a Bosch shop.

Originally Posted by robertobaggio20

Oh I'm such a dud. Its simple to test if the fuel pump is working or not. Just check for continuity.

Bentley tells you which sockets in the fuel pump's connector should possess current. Just switch your multimeter to check continuity in the exact CORRESPONDING prongs on the fuel pump. Switch your multimeter to ohms, low ohms, If it shows, 0, 1 or -1, i.e. no continuity, then the device is dead. No continuity means current cannot continuously flow from one point to the other. There is a break somewhere. That is not normal and usually means the circuits are dead. And if there's no continuity at the fuel pump, that means that even when you connect the fuel connector back to the FP's prongs, current will not be able to flow from the battery through the pump and back to the battery again.

Anyway, from the sound of it, it looks like your fuel pump is working (pressuring sound from the engine) and your fuel relay is not the problem ( no change when you swop with the exact relay from elsewhere in the car). Your fp's fuse is also ok.

Then I think your crankshaft position sensor is screwed. Pull the codes from your car, you should have a CPS code (there are lists of codes on the internet).

If you don't have a code reader or the stomp test does not work, find and unplug the CPS, then test it for continuity. Bentley has details. If it doesn't, then purchase a new one and swop it in. In any case, you should purchase a new one and swop it in, the CPS will fail at some point or the other and you've already wasted so much time with this thus far (which is why the sticky at the top of the list emphasises killing known no-start situations ahead of time).

Only buy OEM. While you're at it, purchase an OEM FP, FP's o ring, and an FP relay. Swop them all in when you have the time.

I checked the continuity of the fuel pump, looks like there's a continuity, I got 7.2 Ohms on terminal 4 (-) and 5 ( +). So looks like the fuel pump might be OK, or perhaps is also possible that the motor might be bad too. I am still wondering why when I jump #30 and #87 on FP relay (Orange), I don't get the engine pressurizing sound like when in key2 position. The fuel pump relay (Orange) I checked, still wondering if it's really a fuel pump relay. I used voltmeter to check #30 and #87, it's has ~0.543 KOhms continuity. I checked #30 and #87 socket where the blue relay at, getting about 92.3 Ohms reading. When car battery is attached, this socket from #30 and #87 on blue relay gets 11.88V.
With car battery, the white relay also has 11.88V when jumping #30 and #87.
Do you guys know if FP relay suppose to have +12V or not when jumping #30 and #87 with battery attached back into the car? On my fuel pump relay, there's NO +12V when jumping #30 and #87 (Orange relay).


Anyway, I think next step is for me to find where the Crankshaft position sensor at. I saw this picture here, it's call crank position sensor, is it the same? It's not crankshaft.
http://www.partsgeek.com/catalog/199...on_sensor.html

Do I need to remove the car hood (prefer not to) to get to the center of car (in between left and right front headlights) to get the CPS? So far I can access the engine area from the side of the hood, kind of hard to reach to the center or low center area.


Also I prefer not to replace everything at once (fuel pump, fuel relay, fuel filter, CPS...), eventually will have to replace all of them, but I will do one step at a time. I can only work on this on my spear time.



BWMFather, what you're saying is Bosch is not OEM part, and the CPS works well on your E23? So you're saying don't have to buy OEM parts? Will not using OEM parts make it hard to install?

Bosch make the OEM part. There is no difference what so ever between a Bosch Bosch part and a Dealer Bosch part. Same in EVERY detail.

If you are pulling relays and the system still pressurises in Key position 2 you still haven't found the correct relay. From memory, terminal #30 will be permanent power and #87 where the wire to the load (fan/pump/light) is attached. Keep that meter in VOLTS, unless you are checking the resistance of a disconnected unit.